From the beginning, communities have tried to resolve the problem regarding the disposal of the Residential Solid Waste (RSW). At first, the treatment methods consisted of the application of highly poor and rudimentary systems, essentially consisting of open dumps, emptying into the ocean, composting and, finally sanitary landfills where the mentioned RSW is accumulated forming a critical dangerous mass, with the consequent problems coming from the natural leaching of the percolated liquids into the groundwater, toxic gas emission such as methane, carbon dioxide and mercaptans resulting from aerobic and anaerobic fermentation of the material contained in the waste and the proliferation of infectious vectors, such as dogs, birds, rodents and other animals that can feed themselves with the waste present at the open dumps.
Subsequently, in Europe and United States of America the need of more complex treatments was imposed as integral solution for the RSW disposal problem. The previous waste pyrolysis and thermogenesis techniques can be mentioned among the most outstanding industrialized processes, which present interesting environmental results, but of great economic cost. Notwithstanding, the waste pyrolysis and thermogenesis processes have the inconvenient of generating an important amount of risky components such as dioxins, carbon dioxide and methane, besides presenting a huge investing cost at the waste combustion stations, which makes it difficult to install such plants in the countries less developed.
Recently and faced to the proximity of new technical environmental demands compelled by the international agreements, it is necessary to design new technological systems and processes based on the compression of the critical RSW mass, the sanitization or disposal of the resulting liquids and the subsequent treatment of the remaining solids.
A system known in the previous art is the Davis and Trash Method, consisting of the compression and sanitization process of solids and liquids with gaseous chlorine as sanitizing agent, where a compression at a 40 kg/cm2 pressure must be performed in the first 72 hours after collecting the RSW. The gaseous chlorine must be injected during the compression stage of the RSW and the evacuated liquids may be spilled into the sewerage system. On the other hand, the dry, inert and bacteria free solids may be disposed in a sanitary landfill, reducing the weight and volume of the initial values with a comparative advantage of approximately 50%. This process has the disadvantage of generating organochlorine compounds, which are highly toxic, being necessary to wash and recover them previously eliminating the steam of the atmosphere.
Another system of the previous art is the one known as Rotomat System, which includes a Huber equipment for separating liquids from solids, pressing and washing the integrated waste, with functions of grinding, washing, extracting, dehydrating, and pressing. The liquids are treated and sanitized through a reverse osmosis, the solids being eliminated in conventional sanitary landfills.
The previous art also shows the process developed by researcher J. M. Baldasan through which no previous treatment of the disposed domestic garbage or of the liquids evacuated is performed. This is due to the fact of proving that such liquids present a lower level of pollution compared with the residential effluents, reason for which they could perfectly be evacuated into the drain pipe or the sewer system and because there is no generation of bacterium of the liquids within the first hours.
For minor communities, the method known as COMPOST could be a good answer to the problem, consisting of the same biological process which performs a decomposition of the contained organic material, such as fruits, green vegetables or vegetables, among others, generating a compost that can be destined to improve the quality of the lands, considering that it is very rich in nutrients. The technique consists of collecting the spare organic material and daily air it, covering it with dry leaves, sawdust, straw or dry grass, in a so-called composter, surface asphalted with side chutes. Layer to layer, the covered organic spares and with the aerobic action of the microorganisms, become leaf mold after several weeks, with fragrance characteristics similar to a wooded soil. Its about a disposal method adapted at a lower level, but not at the level of a particular country or city, being useful as a partial solution for the organic material, but contributing to relieve in some way the index of 1.2 kg of residential waste per person per day.
Other waste disposal processes are described in the Chilean patent applications CL 1143—2001, submitted by the firm DER GRUNE PUNKT—DUALES SYSTEM DEUTSCHLAND AG, with the priority DE 10024309.6, CL 464—1994, submitted by the firm EVERGREEN GLOBAL RESOURCES, INC, with the priority U.S. Ser. No. 08/200,782, and the CL 1412—1999 application, of ERNESTO DE LA CONCHA ESTRADA. Particularly, the document CL 1143—2001, describes a procedure for the dry separation of garbage with plastic material containers waste made up of specific polymers. The CL 465—1994 patent application, describes a procedure of three stages for treating the solid waste and avoid its inherent risks, with recovery of the metallic and energetic useful components, through stages of mechanic and chemical processing. Finally, the CL 1412—1999 patent application describes a method destined to previously select the recyclable garbage and the non-recyclable metals.